ABSTRACT: Dissemination of High-Risk and Novel ESBL-Producing E. coli Clones Across One Health Interfaces in Nine African Countries: A Whole-Genome Perspective from the SeqAfrica-FAO Network
Project description:Background: It remains unclear how high-risk Escherichia coli lineages, like sequence type (ST) 131, initially adapt to carbapenem exposure in its progression to becoming carbapenem resistant. Methods: Carbapenem mutation frequency was measured in multiple subclades of extended-spectrum β-lactamase (ESBL) positive ST131 clinical isolates using a fluctuation assay followed by whole genome sequencing (WGS) characterization. Genomic, transcriptomic, and porin analyses of ST131 C2/H30Rx isolate, MB1860, under prolonged, increasing carbapenem exposure was performed using two distinct experimental evolutionary platforms to measure fast vs. slow adaptation. Results: All thirteen ESBL positive ST131 strains selected from a diverse (n=184) ST131 bacteremia cohort had detectable ertapenem (ETP) mutational frequencies with a statistically positive correlation between initial ESBL gene copy number and mutation frequency (r = 0.87, P<1e-5). WGS analysis of mutants showed initial response to ETP exposure resulted in significant increases in ESBL gene copy numbers or mutations in outer membrane porin (Omp) encoding genes in the absence of ESBL gene amplification with subclade specific adaptations. In both experimental evolutionary platforms, MB1860 responded to initial ETP exposure by increasing blaCTX-M-15 copy numbers via modular, insertion sequence 26 (IS26) mediated pseudocompound transposons (PCTns). Transposase activity driven by PCTn upregulation was a conserved expression signal in both experimental evolutionary platforms. Stable mutations in Omp encoding genes were detected only after prolonged increasing carbapenem exposure consistent with clinical observations. Conclusions: ESBL gene amplification is a conserved response to initial carbapenem exposure, especially within the high-risk ST131 C2 subclade. Targeting such amplification could assist with mitigating carbapenem resistance development.
Project description:The present study examines changes in global gene expression patterns and in virulence factor-associated genes in an extended spectrum beta-lactamase (ESBL)-producing UPEC (ESBL019) during the morphologic transitions induced by an ineffective antibiotic and in the presence of human primary bladder epithelial cells. The morphological shifts induced by ineffective antibiotics are associated with significant transcriptional virulence alterations in ESBL-producing UPEC, which may affect survival and persistence in the urinary tract.
Project description:Colectomy is the most commonly used therapeutic approach for the treatment of non-metastatic colorectal cancer. This approach is generally very effective however the rate of recurrence and the appearance of metachronous metastasis remains a major problem in the postoperative period. One of the hypothesis that can explain this tumor progression is the dissemination of tumor cells at the time of tumor mobilization. In this work, we wish to verify this hypothesis by comparing two surgical technics used in our department for left or right colectomies: respectively either first section of the mesenteric vessels followed by the mobilization of the tumor or first mobilization of the tumor followed by the section of the mesenteric vessels. To evaluate the dissemination, we will study two disseminations markers that have shown their prognostic value: i) circulating tumor cells (which represent a direct marker of dissemination) and ii) tumor circulating DNA (which is an indirect marker) but has the advantage of being more representative of all tumor clones and therefore the tumor burden released into the blood at the time of surgery).
Project description:Little is known about metabolic changes accompanying endothelial cell (EC) quiescence. Nonetheless, when dysfunctional, quiescent ECs (QECs) contribute to multiple cardiovascular diseases. ECs need fatty acid β-oxidation (FAO) for proliferation. Surprisingly, we now report that QECs are not hypo-metabolic, but upregulate FAO >3-fold higher than proliferating ECs (PECs), not to support biomass or energy production, but to sustain the TCA cycle for redox homeostasis through NADPH production. Hence, inhibition of FAO-controlling CPT1A promotes EC dysfunction (anti-fibrinolysis, leukocyte infiltration, barrier disruption) by increasing oxidative stress in CPT1AΔEC mice with endothelial CPT1A loss. Mechanistically, Notch1 orchestrates the use of FAO for redox balance in QECs. Supplementation of acetate (metabolized to acetyl-CoA) induces vasculoprotection against oxidative stress and EC dysfunction in CPT1AΔEC mice, possibly creating therapeutic opportunities. Thus, ECs use FAO for vasculoprotection against their high oxygen (oxidative stress-prone) milieu, and for different metabolic purposes dependent on their proliferation versus quiescence status.
Project description:In cancer patients, metastasis of tumors to sentinel lymph nodes (LN) predicts disease progression and often guides treatment decisions. The mechanisms underlying tumor LN metastasis are poorly understood. Using comparative transcriptomics and metabolomics analyses of primary and LN metastatic tumors in mice, we found that LN metastasis requires that tumor cells undergo a metabolic shift toward fatty acid oxidation (FAO). Transcriptional co-activator yes-associated protein (YAP) is selectively activated in LN metastatic tumors, leading to upregulation of genes in the FAO signaling pathway. Pharmacological inhibition of FAO or genetic ablation of YAP suppressed LN metastasis in mice. Several bioactive bile acids were highly accumulated in the LN metastatic tumor. Inhibition of FAO or YAP may merit exploration as therapeutic strategies for mitigating tumor LN metastasis.
Project description:Type 1 interferons (IFNs) induce complex responses that can be beneficial or deleterious, depending on context. Greater understanding of the mechanisms of action of these cytokines could allow new therapeutic approaches. We found that type 1 IFNs induced changes in cellular metabolism that were critical for changes in target cell function. This was apparent in plasmacytoid dendritic cells, which are specialized for type 1 IFN production, where toll-like receptor-9 (TLR9)-dependent activation was found to be dependent on increased fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS) induced by autocrine signaling through the type 1 IFN receptor (IFNAR). Type 1 IFNs also induced FAO/OXPHOS in non-hematopoietic cells and were found to be responsible for increased FAO/OXPHOS in virus-infected cells. Increased FAO/OXPHOS in response to IFNAR signaling was regulated by the nuclear receptor PPARα. Our findings reveal PPARα/FAO/OXPHOS as potential targets to therapeutically modulate downstream effects of type 1 IFNs. mRNA profiles of overnight stimulated plasmacytoid dendritic cells, activated with CpG or INFa. Samples analyzed in triplicate, with HiSeq 2500 byâ/ 50bpX25bp pair-end sequencing